1. Field of the Invention
The present invention relates to an apparatus for providing a cooling water to a spent fuel pool, and more particularly to a passive cooling apparatus of a spent fuel pool in which, when a power is disconnected to a pump for supplying the cooling water due to an accident and thus the spent fuel pool's cooling capacity is disrupted to deplete the cooling water, the cooling water is supplied to the spent fuel pool, without a separate power supply, according to a water level of the cooling water in the spent fuel pool, thereby preventing or delaying a damage to the spent fuel pool.
2. Description of the Related Art
When storing nuclear fuel, especially in case of storing a spent nuclear fuel prior to final disposal, it is essential to store the nuclear fuel in a manner such that a criticality safety is maintained, decay heat is removed, radioactive materials are sealed, and human beings and the environment are sufficiently protected from radiation.
A wet storage method in which spent nuclear fuel is stored in a storage tank has been widely operated in various countries up to the current time, and is a well established technology for storing the spent fuel.
Generally, an aggregate of the spent fuel is stored in a storage rack within the storage tank composed of concrete materials, and the storage tank is usually lined with stainless steel or epoxy paint.
Typically, in a conventional method of cooling a spent fuel storage tank, radioactive decay heat generated in the spent fuel is removed by forced cooling using a heat exchanger and a temperature of cladding is maintained at 30˜40° C. during an operation, and therefore, it is advantageous in that a storage density is higher than in case of a dry storage method. However, the conventional forced cooling method using the heat exchanger has a serious problem such that, when a power supply is stopped due to an accident, a cooling function becomes disabled and the nuclear fuel is exposed by depletion of the cooling water.
In addition, with respect to the storage of the spent fuel, U.S. Pat. No. 5,488,642, titled “COOLING SYSTEM FOR SPENT FUEL,” published on Jan. 30, 1996 discloses a cooling system of the spent fuel pool; however, this system requires an operation of, for example, a heat exchanger or a pump, and thus, a supply of electric power is still required. Thus, this system fails to teach a cooling apparatus according to the present invention for supplying a cooling water without power supply in the event of an emergency situation where the power supply is disrupted.